Time and Back Again
by MustacheOn
Summary: It was a mystery to Allen how one minute he was almost killed by an Akuma, amidst the war in year 18XX, and the next he was stuck with most promising entrepreneur in New York, Kanda Yuu. Now, Allen has to find a way to get back and end the war, even if it means to forever lose the bastard he's slowly falling for. Yullen. Time travel AU.


_Originally I planned to make this a one shot, but after 11 Word pages and not being even near the half of this story – well, turned out to be a multi-chapter. So!_

 _Warnings: First Yullen. Spelling and grammar mistakes. Constant Change in POV (There will be a page break to differentiate). I hope it won't turn out to be too confusing, though._

 _And no, I haven't abandoned_ **Light Headed** _, but since my laptop is shit, I had to rewrite the whole next chapter and its taking me longer than I planned. Good news is I'm almost done!_

 _Enjoy!_

* * *

In a sick, twisted and depressing way, it was stupid, Allen thought, how he'd been fighting a war for as long as he could remember, and all for one man. One insanely powerful man, and his equally powerful family, but still.

Fire crawled out from the already damaged buildings, dark smoke covered the otherwise grey sky, and he could hear the heart-wrenching cries from both, allies and enemies alike. An Akuma had grabbed a blond finder and dragged him all the way up, towards the burning building, his screams barely audible amidst the cries of war; but all Allen wondered was why the hell was he feeling so calm, so – so at peace with himself?

A sick, wet 'plop' at his side drove Allen out of his musings. Akuma, he dully noted, as the dark blood of the lifeless body trailed a lazy path all the way to his right foot, before the body turned itself into dust and his left eye could see the trapped soul no more.

He stared at the bloody trail, his hand carefully reaching towards it until his index finger touched the sticky, crimson liquid.

It was as if something had snapped inside Allen, then. His breath started to shorten and his hands started to tremble. He felt his heart drop all the way to his stomach and he could finally feel the pain in his right leg, where he'd been stabbed.

 _No, no, no, no._

There was so much blood.

He was at war. He was at war and the screams and bodies and the red stained floor was everywhere around him, the air was heavy with death and the pain was still there, slowly tearing his leg from the rest of his body.

His breaths shortened even more as his silver eyes focused on his blood stained finger. He frantically wiped his whole hand on his torn, black exorcist coat, and the blood was gone but it wasn't really. It had permeated underneath his skin, marking him with death and guilt and murder – and he could no more.

He raised his hands and gripped the back of head tightly, making himself smaller as he brought his knees up and buried his face between them, rocking himself back and forth.

 _Why, why, why, why?_

In a sick, twisted and depressing way, this war was slowly tearing him apart.

Allen dragged his hand all the way from the back of his head to his eyes, and he stared at them. Blood stained and cold.

He remembered now, why he felt so calm, so at peace with himself. An Akuma had knocked him down, and he'd hit his head in the process. He felt so light headed – he'd lost so much blood.

Allen barely distinguished if all that yelling was from his comrades or his enemies. This was bad, he had to go back, he had to keep fighting.

He tried to stand up but his legs gave up beneath him; his head was spinning and his sight was turning blurry and–

Suddenly, all was silent. He couldn't hear the cries of his friends, or the yelling of his enemies, or the sound of the cannons, just, _nothing._ Nothing but the soft sound of shoes hitting the ground, quickly approaching him. He should reach out, ask for help, ask what was going on but–

Everything was going dark and – ah. He'd lost too much blood.

He only wondered if the muted yelling he was hearing was, once again, from his fallen comrades.

* * *

It was in the middle of the night on his way back home that Kanda decided he wanted to murder his two so called 'best friends'.

His day had started quite normal, actually. Wake up, meditate for a while, assort some paperwork because, even if he was only 25, Kanda was one of the most promising entrepreneurs in New York, according to the occasional news and those business magazines that you could get pretty much everywhere.

It was at about 3 in the afternoon on Saturday, that he'd finished with all work related paperwork and decided to go and grab some lunch at that small restaurant just a couple of minutes away from his penthouse.

He certainly hadn't expected to see Lavi and Lenalee there, also eating lunch. What he did expect, of course, was for Lavi to notice him before he managed to get away from the store. He swore that Lavi had some sort of Kanda-radar attached, maybe besides his idiotic and hyperactive switch that always seemed to be turned on.

"Ah, Yuu!" he called, and Kanda groaned internally as he turned around to glare at the red haired man. "Fancy meeting you here; come, sit down with us."

"I told you not to call me that, idiotic rabbit," Kanda said with as much venom as he could muster. Lavi, of course, just brushed him off with a goofy grin.

"You know, Lena and I were just talking about you," he said as he pointed at Lenalee with his half eaten French fry. "We wanted to go clubbing tonight and you'll be coming with us, of course. Chaoji, Daisya, Marie and Miranda are also coming. Krowly said he had a date with Elialde, though, and –"

"No," Kanda interrupted glaring heatedly at the pouting redhead.

"But Yuu –"

"Kanda," Lenalee interrupted, before the long haired man could lounge himself at Lavi and strangle him right there and then. "You know, tomorrow is my birthday and I'm going to spend it with brother, that's why _I_ was the one that proposed tonight's plan, and you're not going to let me down on _my birthday,_ are you?"

Kanda's hands twitched with the irk to strangle the sniggering rabbit in front of him, but controlled himself as he watched Lenalee's sweet, innocent smile that promised pain and murder if he dared to say no.

She was a terrifying woman.

"Che, fine," he said as spitefully as he could muster, willing his words to show Lenalee just how much he hated being blackmailed by her, to which she just shrugged him off and positively beamed at him.

"Great!" she said, clasping her hands together and radiating happiness all around. "We'll pick you up by 9, because we don't trust you to go on your own."

And that was how Kanda found himself walking back home, in the middle of the night and through an empty park because he absolutely hated crowds, and he'd be damned if he waited for his idiotic friends to tire of the damned party.

Besides, he found out that the cool breeze of the night sort of soothed him.

Kanda glanced up as he shoved his hands down his black, fitting jeans. There was no moon tonight, and there were no stars to see. It was somewhat nostalgic, although he had no idea why.

In a second, the air then turned slightly chillier, and the night grew somewhat darker, and an odd feeling crept in the back of Kanda's mind as he lowered his head again and saw a dark lump of _something_ blocking his way.

He stared, standing still for a whole two minutes before he realized that the black lump slightly moved up and down, just barely, as if breathing. The smell of blood filled his nostrils then, and Kanda felt as if someone had just poured a bucket of ice on him, because that was not _something,_ but rather _someone._

"Hey," he whispered, taking a careful step forward and followed by hurried ones immediately. "Hey! Are you alright? What happened?"

He knelt down besides the lump to see the pained face of a boy – _a boy_ , clearly younger than him, contorted with pain as shallow breathes leaved his parted lips. His unfocused silver eyes landed on Kanda, seeing past him before slowly shutting themselves.

"No, wait, shit," Kanda cursed, carefully hoisting the lithe body up as he rushed down the park. "You'll be all right, hang on."

His home was just a few meters away.

He started calling a doctor.

* * *

" _Hey, Master," Allen said, exhaustion clear in his ten-year-old face as he tried hard to even his breath._

" _What is it, idiot apprentice?" Cross asked, not bothering to look up from his newspaper._

 _Allen fidgeted for a while, turning his innocence activated arm back to its_ human _form, "Why are we fighting this war?"_

 _A heavy silence invaded the room for a short while that felt like an eternity. A long sigh escaped Cross' lips before he placed the newspaper down on the coffee table and turned his attention to the fidgeting white haired child, "Because we would die if we don't fight."_

 _Allen fidgeted some more, "Do you think Mana would be proud of me, here, like this?"_

 _Cross never gave him an answer, but it was all right; Allen was not expecting one. He knew this was not what Mana would've wanted for him._

 _He wouldn't be proud, he'd be sad._

 _A blank expression adorned the child's face as he peeked out through the window, today the sky looked beautiful._

* * *

Allen woke up with a start, the last traces of his dream silently vanishing before he even had the chance to miss them. White ceiling greeted his silver eyes, he turned his head left and saw velvety chocolate curtains, going all the way from the ceiling and pooling lightly to the ground.

He frowned. His room back at the order lacked such elegant curtains; hell, he even lacked a proper window.

Just where the hell was he?

Allen tried to sit up, but a striking pain in his leg followed by a sudden dizziness plopped him back to the soft mattress. He groaned, covering his eyes with the back of his forearm and waited for a couple of seconds as his body adjusted to the pain. Slowly, he uncovered his eyes and turned his head the other way; wherever he stared, this room screamed luxury at the top of its lungs.

It was a simple yet elegant room. The bed was big and soft, colored in white and chocolate combining perfectly with the curtains. Allen reckoned that at least two other people could sleep in that bed comfortably. There were two bedside tables, each with a gold and brown lamp. On the wall opposite to him was a clean, simple desk. A couple of notebooks and books resting in it, and on each side of the desk, stood two wooden, large bookcases, going all the way from the floor to the ceiling. Each one filled with books.

To his right, Allen could see a closed door which he assumed was the one that lead outside of the room, and on the corner behind him, Allen could barely see a walk-in closet and what he thought was the door to the bathroom.

All in all, Allen was pretty sure he was dreaming.

That is, until the door to his right opened to reveal a long haired person standing by the doorframe. A glass of water and some pills on one hand, and for some alarming reason, a katana in the other.

"About time you got up," he said, walking with long steps towards Allen. "Take this, doctors' orders."

Allen obliged, taking the medicine from the scowling man and swallowing it in one big gulp. Allen looked back to the man and noticed his slightly disheveled form; long strands of hair falling from his loose ponytail, and a thin coat of sweat covering his forehead. His katana rested lightly on his shoulder.

Originally, Allen wanted to say thank you to the man for taking care of him, but somehow the words got lost on the way from his mind to his mouth, and instead Allen blurted a, "you're a guy?"

In a swift, fluid move, the katana was firmly pressed on Allen's throat; he vaguely wondered when had the man unsheathed his weapon before he shivered involuntarily. Maybe he'd slightly screwed up.

"I-I'm sorry!" Allen said, lifting his hands in surrender. "I meant to say thank you, really, my mind must still be a bit fuzzy – please don't murder me."

He sighed relieved when the apparent samurai sheathed his sword and placed it carefully by the bedside table. He clicked his tongue in obvious annoyance and gave Allen a rather nasty glare.

"Fucking, ungrateful beansprout," he said. "If it wasn't for your wounds I would've kicked you out already."

A slight twitch made itself present on Allen's left eyebrow, but he decidedly ignored it, placing his best smile on before addressing the older man, "yes, about that, thank you for taking care of me. My name is _Allen_ , by the way, and you are…?"

"Che," the man scowled, wrinkling his nose in disgust.

 _Why, this cocky bastard,_ Allen thought, but held his smile in place, tilting his head to the side in mock curiosity and wishing the bastard would get a clue and answer the question.

"Kanda," the man said, going over and opening the curtains before taking a seat in the corner of the bed, arms crossed and scowl still in place as he not-so-discretely took a better look at the young man in his bed.

"Well, thank you, Kanda," Allen said, ignoring Kanda's curious look as he stretched his arms above his head. "Though I should get going, my friends must be – actually, how did I get here?"

"Che," Kanda scoffed, "that's what I'd like to know. I found you alone on my way back home, all bloody and unconscious in the middle of the night before bringing you here."

Allen blinked a couple of times. Alone? But he was in the middle of a war! He turned his head to the side and for the first time looked at the scenery from his window. The sun hung low in the sky, hiding behind the tall buildings that seemed to be everywhere, some of them with many lights in them. Images were projected against a building near him and he could see a girl modeling a bathing suit. Everything was new to him, even the sounds he could not recognize.

Allen felt his heart tightening; this was not London.

"Kanda," he said, eyes not leaving the window, "where am I?"

"In my house,"

"No, I mean," Allen started, eyes landing on the confused older man. "This is not London, right?"

"This is New York," Kanda said, brows furrowing in slight concern.

Allen stood up and walked towards the open window. He heard some shuffling from the bed and soft footsteps stopping a couple of feet behind him.

New York? But he'd been in New York last year, with Master, and it wasn't like this at all! Allen heard a soft rumbling above him and he looked up to see a metal _something_ soaring through the sky. He suddenly started to feel dizzy; his heart once again was sinking to his stomach while it made a painful knot.

"Kanda, what year is this?"

"2016,"

Allen felt like he was going to be sick, his head started pounding and his vision got blurry. Before he knew it, everything went dark.

* * *

Kanda placed the unconscious boy carefully on the guest room's bed, glad he'd been standing just within arm's reach when the kid had suddenly passed out.

He carefully placed the covers over the sleeping boy and frowned. London? What year was this? He reached out and placed a hand over Allen's forehead. He had a slight fever.

 _Either he's delusional from the fever, or he's just mental,_ Kanda thought. He glanced at Allen's battered and bloody coat hanging from the back of a chair. Of course, the other reason behind the boy's actions was abduction. Maybe he was from London, and had been abducted some years ago and had no clue as to what time it was now?

Kanda shivered involuntarily, his train of thought had gone from bad to worse, and he found himself hoping nothing like that had happened to the boy. Although by his slightly muscular frame, it seemed quite far-fetched.

Maybe, after all, the kid was mental, and Kanda should've called a mental hospital.

He groaned and left the room, there was no way to know until he woke up and there was no need to worry about that, at all. In fact, there was no need for Kanda to be worrying about some random kid he found on the street! Tomorrow morning he would call the police and let them take over this case, everything else be damned.

He stormed to the kitchen and made himself a cup of tea, his mind going back to Allen's red arm and its green cross.

The boy had been used to it, it seemed, since he made no effort on hiding it whatsoever, which made Kanda wonder just how he'd managed to hurt himself like that, and how long had it been since. The Doctor had mentioned that maybe he'd been born with it, like a malformation from birth. That, or an unfortunate fire.

Then there was his left eye. What he had thought to be a careless tattoo in an even more careless place, under closer inspection proved to be in fact a scar. It smudged in the corners, and the skin seemed different there, as if exposed yet not quite healed by the redness of it.

And his _hair_. Was it even real? God, the kid stood out like a sore thumb. He barely wondered if he'd been bullied at school with all that.

Kanda walked back to his living room, cup of green tea in hand and gracefully seated himself in front of his TV. He went through the channels carelessly, not really paying attention on what was playing in his wide screen as his thought went back to the sleeping boy.

He groaned. _A boy._

Really, he couldn't be older than 15. And to be found all bloody and battered in the middle of the night? He just hoped he wouldn't be unfairly charged for child abuse.

Kanda turned off the T.V., deciding there was nothing he really wanted to watch and opted for his unfinished novel instead. A book Lavi had recommended him about a tragic incident in a laboratory in Japan, where scientists had incubated humans by implanting them the memories of fallen soldiers. Based on a true story, it said, but Kanda found it as nothing more than interesting fiction.

Time passed Kanda without him really noticing. He stirred in his couch and picked up his phone, it read 10:52 p.m.

He placed the book on the coffee table before him and left his dirty tea cup in the kitchen before heading to his room. Might as well get some sleep now, if he planned to get rid of the kid first thing in the morning.

He stopped at the front of the guest bedroom door, which was right before his room. He hadn't checked on the kid at all since he'd passed out.

With a groan, Kanda quietly opened the door, seeing through the stream of light that leaked from the corridor. There was Allen's lithe form, shifting and tossing under the covers. Light mumbling caught his attention and Kanda walked closer, leaving the door open as to not collide against the furniture. Allen's face was flushed, eyes tightly shut with shed tears wetting his flushed cheeks and sweat marring his childish features.

"No, no, no, no," he kept mumbling.

Kanda wasn't aware when he'd sat on the bed – near the boy's chest, nor when his hand had suddenly, gently, stroked away the tears from Allen's cheeks, whispering comforting nothings in an attempt to calm him down.

"It's just a bad dream," Kanda said. "You're fine, beansprout."

A sudden chill engulfed the room, then; much like the time he had found Allen the night before. His red hand suddenly shot up and grabbed Kanda's hand with a strength he didn't know the kid possessed.

"Wha– Beansprout?" Kanda said, when the green cross in Allen's hand glowed brightly, engulfing them both in a blinding light and making Kanda cover his face with his free hand.

First, he felt the cold wind ruffling his hair; Kanda didn't remember opening the guest room's window. Then, the stench of death and blood hit him hard and cold. Slowly, he lowered his arm from his eyes, and just then did he realize there was screaming around him.

 _This can't be happening, I – where am I?_ Kanda thought. He looked around, there were lifeless bodies left and right, some of them dressed with the same black coat he'd found Allen with. Disgusting creatures hovered in the sky with weapons he'd never seen before. A sudden ear-splitting shriek caught Kanda's attention, and he looked up just in time to see a blond man being ripped in two by a white creature with large, claw-like hands. Its white body now covered with splotches of blood. A wicked laugh escaped the monster's lips as it kept chanting, "I killed the exorcist, I killed the exorcist!"

Kanda couldn't take it. He fell to the ground in all fours, his face above Allen's; a sick feeling making its way to the pit of his stomach. He saw a trail of blood slowly, lazily making its way to his right hand. He hurriedly got up, scared that if the blood touched him this would become real, because it had to be a nightmare – _It had to be._

He leaned on the piece of a fallen building which was currently covering them from the monsters and humans alike. He didn't trust his legs to support him on their own.

Just what was this? Where was this? He was in his penthouse just a moment ago, how'd he get here to begin with?

Slowly, he leaned down next to Allen, shaking him forcefully in a failed attempt to wake him up.

"Beansprout," he mumbled, "wake up, we need to get out of here."

"Out where?"

Slowly, Kanda turned around to see the wicked smile of the monster that had ripped the blond man from before. His overlarge hands still bloody.

"Shit," Kanda said, standing up in a hurry and making to grab his katana, just to realize it wasn't with him.

"If I kill you both, I'll be a level 3," the monster said with glee, sharp razors growing out of its fingers as it prepared itself to attack. "Die, exorcist!"

Kanda closed his eyes, bracing himself for the attack that never quite came. Slowly, cobalt opened to see the monster mere inches away from him, eyes wide and blood trailing down from his mouth.

He took a step away, finally taking notice on the large sword impaled in the monster's stomach.

"May your soul be saved, pitiful Akuma,"

Kanda turned around to the source the cold voice and saw Allen, standing right behind him. His face was stone cold, a white cape fell gracefully by his shoulders, and a silver mask hung at the base of his neck. His left arm was gone, and he held the large, white sword that had rendered the monster to ashes.

His left eye, which had turned black and red, returned to its silver form, and the serious expression that had settled in his childish features turned to a worried one as he drove his attention to a shocked Kanda.

"Kanda," Allen said, taking a step to the side and leaning against the fallen building. "Are you all right?"

Kanda nodded, not trusting his voice at the moment.

"I'm so glad," Allen said, a small relieved smile graced the boy's lips and somehow, the small gesture made Kanda's heart clench with pain.

How could he still manage to put up such a pained smile amidst this bloody war?

A whimper suddenly escaped Allen's lips as he fell to the ground, right hand clutching his now bloody thigh.

"Your wound," Kanda said, kneeling before him. "It's opened, we need to treat you."

Allen's breath left him in pained, short gasps. His eyes were getting glassy and a flush made its way to his face. Kanda placed his hand on the boy's forehead and cursed. He was burning up.

"We need to get you out of here," he said as he carried the boy bridal style. It was his turn to save him now, but where? And _how_?

Adrenaline coursed so fast through Kanda's veins that he almost missed the slight chill that settled around them. The sudden bright, green light had engulfed them once more, and before Kanda knew it, he was standing once again in his guest's bedroom. A panting Allen in his arms and his red arm back again in its socket. The white sword was nowhere to be found.

Fifteen minutes later found Kanda pacing back and forth in his own room. He had managed to subdue Allen's fever but the boy was still out cold, and Kanda needed answers.

With a click of his tongue Kanda decided to ask Lavi about it.

He pulled out his phone from his pants pocket, glad it was still in one piece and unlocked it. He was about to call Lavi when the time suddenly caught his attention.

11:13 p.m.

"What–" but Kanda interrupted himself. That couldn't be right. He had been in that – that _war_ for at least half an hour, but time appeared to not have passed at all, as if it all hadn't happened.

The pained cry of the blond man, right before being ripped in half echoed in Kanda's mind and he stopped himself from vomiting.

It had definitely happened.

He forcefully shoved the thought at the back of his mind and decided to ask Allen about it when he woke up. He needed answers.

He dialed Lavi's number at once, hoping that his annoying friend would just hurry up.

"Answer the damned phone you imbecile, one eyed– "

" _Yuu, my man! What can I do for you this lovely evening?"_

"I need your help," Kanda said, hoping that his serious tone would make Lavi cut all crap.

" _Is everything okay?"_

Kanda sighed in relief; the redhead had apparently caught his urgent tone.

"Tell me everything you know about a war in London,"

" _A war? I need you to be more specific, Yuu – are you really okay?"_

Kanda groaned, that idiot would think he was positively crazy.

"A war with exorcists and Akuma."

There was silence in the other line of the phone, and Kanda barely wondered if Lavi was working on how to tell him he had gone insane. He certainly felt insane.

" _Uh, yeah, the Holly War. There's not much info about it, but I remember gramps telling me it was a war no one knew about, no one but the Vatican. They had soldiers – exorcists, and they fought against this man called the Millennium Earl, a mad man that made demons out of man's grief. It was somewhere around the 1800's, though, and it doesn't sound all that real to me –"_

"Thanks," Kanda interrupted before hanging up.

He went over to his laptop and turned it on; opening Google as soon as it was possible and typed up this Holly War Lavi told him. There were almost 7.3 million results. It seemed Kanda wouldn't sleep much this night, anyways.


End file.
